1 package com.shanhw.javaEnhance.thirteenthDay;
 2
 3 import java.util.Date;
 4
 5
 6 /**
 7  * 自定义类加载器
 8  */
 9 public class MyClassLoaderTest {
10
11     public static void main(String[] args) throws Exception {
12         String path = "E:\\Kingsoft Cloud\\Workspaces\\TestExample\\shanhwlib\\ClassLoaderAttachment.class";
13         Class<?> clzz = new MyClassLoader(path).loadClass("com.shanhw.javaEnhance.thirteenthDay.ClassLoaderAttachment");
14         Date d = (Date)clzz.newInstance();
15         System.out.println(d);
16     }
17
18 }

 1 package com.shanhw.javaEnhance.thirteenthDay;
 2
 3 import java.io.ByteArrayOutputStream;
 4 import java.io.FileInputStream;
 5 import java.io.InputStream;
 6 import java.io.OutputStream;
 7
 8 public class MyClassLoader extends ClassLoader{
 9
10     private static void cypher(InputStream is,OutputStream os) throws Exception{
11         int i = 0;
12         while((i = is.read()) != -1){
13             os.write(i ^ 0xff);
14         }
15     }
16
17     private String classDir;
18
19     public MyClassLoader(String classDir){
20         this.classDir = classDir;
21     }
22
23     @SuppressWarnings("deprecation")
24     @Override
25     protected Class<?> findClass(String name) throws ClassNotFoundException {
26         try {
27
28             FileInputStream fis = new FileInputStream(classDir);
29             ByteArrayOutputStream baos = new ByteArrayOutputStream();
30             cypher(fis,baos);
31             fis.close();
32             byte[] bytes = baos.toByteArray();
33             return defineClass(bytes, 0,bytes.length);
34         } catch (Exception e) {
35             throw new RuntimeException("运行时异常");
36         }
37     }
38 }

 1 package com.shanhw.javaEnhance.thirteenthDay;
 2
 3 import java.util.Date;
 4
 5 public class ClassLoaderAttachment extends Date {
 6     /**
 7      *
 8      */
 9     private static final long serialVersionUID = 1L;
10
11     public String toString(){
12         return "Hello Houwang Shan!";
13     }
14 } 

 1 package com.shanhw.javaEnhance.thirteenthDay;
 2
 3 import java.lang.reflect.Constructor;
 4 import java.lang.reflect.InvocationHandler;
 5 import java.lang.reflect.Method;
 6 import java.lang.reflect.Proxy;
 7 import java.util.ArrayList;
 8 import java.util.Collection;
 9
10 public class ProxyTest {
11
12     /**
13      *
14      */
15     public static void main(String[] args) throws Exception{
16         Class clazzProxy = Proxy.getProxyClass(Collection.class.getClassLoader(), Collection.class);
17         System.out.println("----------Constructors:----------");
18         Constructor[] constructors = clazzProxy.getConstructors();
19         for(Constructor constructor:constructors){
20             String consName = constructor.getName();
21             StringBuilder str = new StringBuilder(consName);
22             str.append('(');
23             Class[] clazzParas = constructor.getParameterTypes();
24             for(Class clazzPara : clazzParas){
25                 str.append(clazzPara.getName()).append(',');
26             }
27             if(clazzParas.length != 0){
28                 str.deleteCharAt(str.length()-1);
29             }
30             str.append(')');
31             System.out.println(str);
32         }
33         System.out.println("----------Methods:----------");
34         Method[] methods = clazzProxy.getMethods();
35         for(Method method:methods){
36             String consName = method.getName();
37             StringBuilder str = new StringBuilder(consName);
38             str.append('(');
39             Class[] clazzParas = method.getParameterTypes();
40             for(Class clazzPara : clazzParas){
41                 str.append(clazzPara.getName()).append(',');
42             }
43             if(clazzParas.length != 0){
44                 str.deleteCharAt(str.length()-1);
45             }
46             str.append(')');
47             System.out.println(str);
48         }
49         System.out.println("----------创建实例对象:----------");
50         Constructor constructor = clazzProxy.getConstructor(InvocationHandler.class);
51
52         Collection collection = (Collection)constructor.newInstance(new InvocationHandler(){
53
54             @Override
55             public Object invoke(Object proxy, Method method, Object[] args)
56                     throws Throwable {
57                 return null;
58             }});
59         Collection proxy = (Collection) Proxy.newProxyInstance(Collection.class.getClassLoader(),
60                 new Class[]{Collection.class},
61                 new InvocationHandler(){
62                     ArrayList arrayList = new ArrayList();
63                     @Override
64                     public Object invoke(Object proxy, Method method,
65                             Object[] args) throws Throwable {
66                         return method.invoke(arrayList, args);
67                     }
68                 });
69         proxy.add("a");
70         proxy.add("a");
71         proxy.add("a");
72         System.out.println(proxy.size());
73     }
74 }